Cant run more than 1 USB device.

USB is 5volts and max 500milliamps. The specification states that with a computer as host up to 127 USB peripherals with 5 levels of hubs can be connected to a single host controller. (I'd like to see that!). So you should be able to run your printer, scanner, flashdrive, keyboard, mouse & whatever else you come up with via an appropriate size USB (powered) hub. If you need more ports the hubs can be daisy-chained.

Your USB 2 drivers are not installed correctly. Either your motherboard CD or your USB 2 driver install disk will take care of the problem. If you have a separate USB 2 install disk use it but IF the motherboard CD also has a USB 2 driver, make sure you install that one first.
Then check with device manager on confirm that the USB 2 drivers (four of five of them) are shown.
I had to do this myself.